Sorry if this has been posted before but I am new to the forums. Just purchased a 1999 Wrangler TJ and I am in love. Within a week of purchase I started hearing a "clacking" noise that sounds like a rock in the hub. Clacks with the speed of the tire it seems. Doesnt matter if gas is applied, in gear or not. I have chrome hubs so nothing in there rattling. Anyone have any ideas of what it could be?